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#1
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Jim Kelley wrote:
Richard Harrison wrote: Iz = Io cos beta(z) Excellent. Roy is telling us that beta(z) at one end of the coil is essentially equal to beta(z) at the other end of the coil. Which requires a lossless, non-radiating coil with zero capacitance. Where can I get one of those? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#2
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![]() Cecil Moore wrote: Jim Kelley wrote: Richard Harrison wrote: Iz = Io cos beta(z) Excellent. Roy is telling us that beta(z) at one end of the coil is essentially equal to beta(z) at the other end of the coil. Which requires a lossless, non-radiating coil with zero capacitance. Just out of curiosity, to which of those characteristics do you attribute the phase delay? 73, Jim AC6XG |
#3
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Jim Kelley wrote:
Cecil Moore wrote: Which requires a lossless, non-radiating coil with zero capacitance. Just out of curiosity, to which of those characteristics do you attribute the phase delay? Speed of light? :-) Seems the primary cause of the phase delay would be the capacitance. In many ways, this discussion has become ridiculous. On 440 MHz, one inch of wire is ~13 degrees. Some gurus would have us believe that a physically small one inch coil is zero degrees?????? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#4
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![]() Cecil Moore wrote: Jim Kelley wrote: Cecil Moore wrote: Which requires a lossless, non-radiating coil with zero capacitance. Just out of curiosity, to which of those characteristics do you attribute the phase delay? Speed of light? :-) The finite speed of light though a finite length of wire, yes. Seems the primary cause of the phase delay would be the capacitance. With regard to coils, I think inductance is probably the more relevant parameter. It's proportional to the number of turns and the length of each turn of wire, and inversely proportional to the length of the bobbin. 73, Jim AC6XG |
#5
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Jim Kelley wrote:
With regard to coils, I think inductance is probably the more relevant parameter. It's proportional to the number of turns and the length of each turn of wire, and inversely proportional to the length of the bobbin. Is that "bobbin" a part of a coil winding machine? Coil form? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
#6
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Cecil Moore wrote:
Jim Kelley wrote: With regard to coils, I think inductance is probably the more relevant parameter. It's proportional to the number of turns and the length of each turn of wire, and inversely proportional to the length of the bobbin. Is that "bobbin" a part of a coil winding machine? Coil form? It's a spool-like object used to constrain the length and diameter of a coil of wire to prescribed values. 73, Jim AC6XG |
#7
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Esteemed Antenna Gentlemen.
I am sorry I could not participate in the heated discussions and do experiments and measurements in the past few weeks. I was QRL, weather was lousy and I caught the nasty flu that I hope to shake off in the South next few days. It looks to me like some made statements (contrary to facts) and now are defending them or going all out to prove they are right. Rather than concentrating on the original question, is the current in the antenna loading coil in typical mobile quarter wave whip same or different on its ends, we are drifting to side shows like how precisely you measured it, what is your guess, theory, toroids etc. To recap, W9UCW measured, I witnessed and new that bottom of the coils get hotter than top ergo, more current at the bottom. W8JI attacked that it can't be, he stated it HAS to be equal, Kirchoff, bla, bla. (Now it is maybe not so equal, length of coil, stray capacitance, phase of moon, but it is the same, even when it isn't. Go figure.) W8JI also proved that he lied when stated that he measured thousands of (what?) coils and they all had equal current. Now he posted some measurements and proved that he was wrong, he measured differences. He doesn't describe his setup, and as Cecil explained, one can rig the coils to have the same current, but in a center loaded resonant quarter wave vertical - no way. Now we drifted to ferrites, we guessed Roy's difference and he measured it, THERE WAS A DIFFERENCE 5% at the base. Is difference not a difference? The first experiment I will do is the "thermal test" - I will take Hustler 80m coil, I have two fishing tank LCD strip thermometers ($2.50 in any pet store) I will stick them on the coil at the bottom, at the top, or in between. I will fire TX to it and video tape the change in temperature with timer running. Really smart gurus should be able to calculate the power and currents from that. If gurus object that thermometers are disturbing the coil. Then the thermal test No2 will be done. I will put higher power to it and see the coil unshrink the tubing from the bottom up. I have done it before and it made me true believer in the phenomena. Next test will be with thermocouple ammeters and next with current probe similar (but better) as W8JI used on his tests and showed on the web page. Then we will try to correlate it with our "obscure theories", then we will write the nice, detailed article that hopefully will help to understand the thing for the other side of the fence gurus. The proof is in reality, W9UCW done it, but that CAN'T BE? Thanks Cecil and others for Herculean task and effort in digging out references and trying to 'splain it. Looks like Krause and others are wrong, but old Belrose error perpetuated in ARRL Antenna Book is right, oh and EZNEC modeling 0 size coil and loading stub differently is right too. W8JI used it as a proof that current can be increasing from the base up to the coil. How come that straight piece of wire (as antenna) can exhibit different current along its length (where is Kirchoff) but when you insert the coil and retune it, that coil "refuses" for current to taper? Take the coaxial wound chokes, coil wound of coax at the antenna terminals can reduce the current flowing in the shield. We know that, or are we going to deny that? How is that COIL different that it has different RF current at its ends? That you can check even with MFJ current meter. I hope that weather gets better, flu goes away and life gives me more time. In the mean time, if you are contemplating to get TenTec Orion, read my first part of review on my web www.K3BU.us 73 Yuri |
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